Duct Systems

Building Cavities Are Not Ordinary Supply Ducts

Can wall cavities be used as supply air ducts?

M1601.1.1

Duct Joints and Seams Must Be Sealed

Do HVAC duct joints have to be sealed with mastic or tape?

M1601.4.1

Ducts Outside Conditioned Space Need Required Insulation

Do ducts in an attic or crawl space need insulation?

M1601.4.2

Flexible and Metal Ducts Need Proper Support

How often do flexible ducts need to be supported?

M1601.4.3

Return Air Cannot Be Taken From Prohibited Locations

Can a return air grille be in a garage, closet, attic, or crawl space?

M1602.2

Return Air Openings Must Be Sized and Located Correctly

Can a furnace closet use the door louver as return air?

M1602.3

Supply Ducts Must Use Approved Materials and Construction

What materials are allowed for HVAC supply ducts in a house?

M1601.1

Underground Ducts Need Materials Listed for Buried Use

Can HVAC ducts be buried under a slab?

M1601.1.2